I have had this happen several times over the last month, itnever happened until I upgraded to SW2008 from SW2007.
When exiting from editing a model within an assembly, or whentrying to MMB rotate the model, my systrem reboots.
Once rebooted, I get a Windows message that says "your system hasrecovered from a serious problem" try these steps to fix.
The first step was to install the latest drivers fr the video card.The video drivers were updated at the upgrade.

The second step was to turn off "hardware accelleration" thiscaused other issues!

Any suggestions?
Windows XP
ATI FireGL T2
2Gb Ram
SW2008 SP3.1SolidworksAdministration